An attack on a luxury Burkina Faso hotel and restaurant popular with foreigners left at least 28 victims, including one American, dead as an Al Qaeda affiliate staked out turf in the region, signaling a troubling surge of extremism.

Four assailants also died in the overnight attack at the Splendid Hotel and nearby Cappuccino Cafe in the capital, Ouagadougou, which was aimed squarely at foreign interests in West Africa, with at least 18 nationalities among the dead.

The State Department identified the dead American as Michael James Riddering. The Associated Press described him as a 45-year-old missionary who was among those killed at the Cappuccino Cafe.

Witnesses said the gunmen appeared to target foreigners when they opened fire, Reuters reported.

Dozens of others were injured, according to Burkinabe authorities. Burkinabe forces freed about 150 hostages from the hotel with the help of French special forces and U.S. reconnaissance and surveillance.

Al Qaeda in the Islamic Maghreb, or AQIM, claimed responsibility for the attack in an online statement, according to the SITE Intelligence Group, highlighting growing competition between Al Qaeda allies and loyalists of a rival group, Islamic State, which has been trying to woo extremists in the region.

The attack comes months after another Al Qaeda affiliate, Al Mourabitoun, launched a similar attack on the Radisson Blu hotel in the Malian capital, Bamako, killing 20 people, including an American aid worker, as well as Russian and Chinese citizens.

As the Burkina Faso hotel siege drew to a close there were reports that two Australians, a doctor and his wife, had been kidnapped in the country’s north, near the Malian border, according to Burkinabe officials.

Until recently, Burkina Faso has been spared the terrorist attacks and kidnappings that have plagued other countries in the region such as Mali, Mauritania, Niger, Algeria and Libya. The first sign of trouble was a kidnapping last April, when a Romanian was seized.

Burkina Faso has played a key role in U.S. counter-terrorism training operations in the region, but has recently been troubled by political instability. An attempt by former President Blaise Compaore to extend his rule sparked a popular revolt in 2014, toppling him from power. Compaore fled to Ivory Coast, but his allies launched an abortive coup last year.

President Roch Marc Christian Kabore was elected in November and sworn into office last month.

Visiting the Splendid Hotel in the aftermath of the attack, Kabore cautioned that citizens of Burkina Faso, who were unaccustomed to such attacks, must learn to be vigilant about terrorism.

“The situation we're experiencing since yesterday in Burkina Faso is unprecedented,” he said Saturday. “These are vile, cowardly acts, and the victims are innocent people.” He said in a radio statement that three of the attackers were women.

The attacks and several recent kidnappings of foreigners in Burkina Faso sent a message that foreign aid workers, diplomats, businessmen and journalists are targets for West African terrorists, as are states that cooperate with America’s counter-terrorism initiatives in the region.

They also mark an upsurge in the activity of Al Qaeda affiliates, after Islamic State last year won the loyalty of the Nigerian extremist group, Boko Haram, which was responsible for more killings than any other militant group in 2015.

Al Qaeda affiliates in West Africa have preyed on countries with political instability, porous borders and lax controls, to embed themselves into the region. Burkina Faso and Mali were both seen as bastions of stability until recent years. As political instability took hold, both proved vulnerable to infiltration by extremists.

The attacks threaten foreign investment in the region, condemning countries to a cycle of poverty and instability, making it easier for terrorist groups to recruit alienated, jobless young men to their cause.

Rivalry between Al Qaeda and Islamic State is playing out across Africa, with the Somali militant group known as Shabab split on whether to join Islamic State. Hundreds of Shabab fighters defected from the group over the conflict, Kenyan officials said last month.

The Ouagadougou attack began about 8.30 p.m. when gunmen stormed the hotel and cafe, killing people and seizing hostages. Burkinabe security forces seized control of the hotel and freed hostages early Saturday.

French forces were flown in from Mali overnight, while the U.S. provided surveillance and reconnaissance assistance, the Associated Press reported, citing an unnamed U.S. defense official.

France, the longtime colonial power in Burkina Faso, has played an aggressive role in trying to crush terrorist groups in the region and intervened in Mali in 2013 after several extremist groups took over half the country.

French President Francois Hollande on Saturday confirmed that French forces took part in the assault that ended the Splendid Hotel attack.